As I mentioned earlier I've recently read through Rousseau's The Social
Contract (not that translation though, mine was by Lowell Blair
in the 1970's), and I'll expand on my initial review ("Wrong, but in interesting
ways") here.

The Social Compact

The most important part of The Social Contract is Chapter VI of
the first book, since this chapter is where Rousseau explains the conditions of
the "Social Compact" itself, at least as he sees it. All the previous chapters
build up to this chapter and all the following chapters build upon it. If the
arguments presented in this chapter are in error the book as a whole collapses
and becomes purely an interesting intellectual curiosity (there are some
sections that still maintain some value in isolation). Unfortunately I would
argue that Rousseau's understanding, as expressed in this chapter, is in error,
and such severe error as to be un-salvageable.

First let us examine Rosseau's own words (emphasis mine):

The clauses of this contract are so determined by the nature of the act
that the slightest modification would make them vain and ineffective; so
that, although they have perhaps never been formally set forth, they are
everywhere the same and everywhere tacitly admitted and recognised, until,
on the violation of the social compact, each regains his original rights and
resumes his natural liberty, while losing the conventional liberty in favour
of which he renounced it.

These clauses, properly understood, may be reduced to one - the total
alienation of each associate, together with all his rights, to the whole
community; for, in the first place, as each gives himself absolutely, the
conditions are the same for all; and, this being so, no one has any interest
in making them burdensome to others.

And as to why this must be so:

... if the individuals retained certain rights, as there would be no
common superior to decide between them and the public, each, being on one
point his own judge, would ask to be so on all; the state of nature would
thus continue, and the association would necessarily become inoperative or
tyrannical.

What man would give every part of himself to society; not just his body and
his efforts, but even his opinions, since Rosseau claims that men judging
between themselves and society would cause the contract to become inoperative?
It seems that only an absurdly trusting man would join such an association
willingly and that most men would only join such such an association by force.
As Rousseau himself argues earlier (in Chapter III) force does not make
right, with the result that such a contract, created by force, would be
invalid.

I doubt that men sufficiently trusting and naive to join such an association
exist even in small numbers, let alone the numbers necessary to form a society,
but for the sake of argument let us assume that they do. Would not at some point
these people judge the actions of society (it does not seem to matter whether
they judge them as right or wrong in Rousseau's opinion), or at least their
descendants? At which point society either ceases to exist or reverts to
tyranny.

It seems extraordinarily unlikely that such a society would come into existence
or last for any length of time if it did. Rousseau's writings on how to best
structure society are consequently irrelevant to any real society, and are only
of interest as a thought experiment.

The Marks of a Good Government

As another example in a less important way Rousseau also errs in his
discussion of the best way to measure the whether a government is good or
ill:

But if it is asked by what sign we may know that a given people is well
or ill governed, that is another matter, and the question, being one of
fact, admits of an answer.

...

For my part, I am continually astonished that a mark so simple is not
recognised, or that men are of so bad faith as not to admit it. What is the
end of political association? The preservation and prosperity of its
members. And what is the surest mark of their preservation and prosperity?
Their numbers and population. Seek then nowhere else this mark that is in
dispute. The rest being equal, the government under which, without external
aids, without naturalisation or colonies, the citizens increase and multiply
most, is beyond question the best. The government under which a people wanes
and diminishes is the worst. Calculators, it is left for you to count, to
measure, to compare.

This is obviously absurd. For example using the birth and death rates listed
on Wikipedia the best government in the world is Mali and the worst is Ukraine,
China is somewhat worse than Australia or the US (which are about the same), but
significantly better than Canada, and Mexico is significantly better than
the US, even though huge numbers of Mexicans risk their lives every year to try
to get from Mexico to the US. While it probably made a bit more sense in the
time's prior to birth-control, it still doesn't work. A government could simple
require each woman who wasn't currently pregnant or nursing a child to visit
the local "love shack" once a week. This could easily double the actual birth
rate of a nation, yet I'm sure most people would agree that it would actually
make the government worse.

Slavery and Taxes

As I mentioned earlier, though the central premise of this work is nonsense,
there are some individual chapters that are still of some small value in
isolation. Chapters
III and IV of the first book are of some value as arguments
against slavery and "might makes right", though Rousseau does make several
assumptions that I disagree with (in fairness I suspect he may have covered
these more in his Discourse on Inequality which was written earlier than
The Social Contract, but which I haven't read). Another section that stands out is the first part
of Chapter XV of
the third book, where he states that he "... hold[s] enforced labour to be less
opposed to liberty than taxes." I don't know if I agree with him on this, but I
do know that if we where forced to work one day out of two for the Government
our taxation burden would be much more obvious, and I suspect more likely to be
opposed.

Conclusion

Rousseau's Social Contract is really only of use as an intellectual
curiosity. Due to his fundamental misunderstanding of human society any
attempt to structure a government based on his recommendations would be a
mistake, quite probably a tragic mistake. If you're reading it to expand your
intellectual horizons, as I was, you may gain something (particularly from the
first book), but if you want to improve your knowledge of good government you
will be sadly disappointed.